Mar. 10, 201610:50 AM PT11:50 AM MT12:50 PM CT1:50 PM ET18:50 GMT2:50 AM 北京时间11:50 AM MST1:50 PM EST12:50 PM CT22:50 UAE13:50 ET17:50 - The Panthers signed Gradkowski to a three-year contract.Analysis: Gradkowski is expected to back up Ryan Kalil, the team's All-Pro center. He played in 40 games during three seasons (2012-14) for the Baltimore Ravens, starting all 16 in 2013. Last year he played in three games for the Atlanta Falcons, starting one.